The California-Arizona and Oregon/Hawaii Nodes of the National Drug Abuse Treatment Clinical Trials Network (CTN) integrated their Regional Research and Training Centers (RRTCs) and, in partnership with their community treatment programs (CTPs), combined to propose the Western States Node. In addition to its charter treatment partners, the node expands to include Colorado's network of addiction treatment services - Signal Behavioral Health Network; Signal has prior CTN experience in the Rocky Mountain Node. This competing renewal application has one goal: Promote evidence-based drug abuse prevention and treatment services through our continued participation in the National Drug Abuse Treatment Clinical Trials Network: Design and implement clinical trials of behavioral, pharmacological and combined interventions for drug use disorders through rapid recruitment of diverse study participants in partnership with NIDA and the CTN. Generate peer-reviewed publications in collaboration with treatment providers and other nodes, and Use the CTN as a platform for training, dissemination, and research applications. During the current funding period the California-Arizona and Oregon/Hawaii Nodes, together demonstrated high-quality participation in 12 CTN multi-site clinical trials, involving 13 CTPs and randomizing 900 protocol participants. Node investigators co-led CTN trials of HIV Risk Reduction (CTN0017) and HIV Rapid Testing (CTN0032). Node investigators also sought and received awards for 11 studies that used the CTN as a platform for research. The Western States Node research agenda proposes using the CTN to collaborate with health plans and/or addiction treatment centers to test prevention and treatment interventions directed at reducing the misuse and abuse of prescription opiates. Closing the gap between research and treatment is one of the most critical unresolved issues in drug abuse, and the CTN has a significant role. Based on the Western States Node's experience, access to unique and hard-to-reach populations, and a knowledgeable team of investigators and CTPs, this research node has the potential to accelerate the advancement of clinical trials and translational research in the coming years.